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/*
 * LocalVariableTypeTable.java
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common
 * Development and Distribution License("CDDL") (collectively, the
 * "License"). You may not use this file except in compliance with the
 * License. You can obtain a copy of the License at
 * http://www.netbeans.org/cddl-gplv2.html
 * or nbbuild/licenses/CDDL-GPL-2-CP. See the License for the
 * specific language governing permissions and limitations under the
 * License.  When distributing the software, include this License Header
 * Notice in each file and include the License file at
 * nbbuild/licenses/CDDL-GPL-2-CP.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun in the GPL Version 2 section of the License file that
 * accompanied this code. If applicable, add the following below the
 * License Header, with the fields enclosed by brackets [] replaced by
 * your own identifying information:
 * "Portions Copyrighted [year] [name of copyright owner]"
 *
 * Contributor(s):
 *
 * The Original Software is NetBeans. The Initial Developer of the Original
 * Software is Sun Microsystems, Inc. Portions Copyright 1997-2006 Sun
 * Microsystems, Inc. All Rights Reserved.
 *
 * If you wish your version of this file to be governed by only the CDDL
 * or only the GPL Version 2, indicate your decision by adding
 * "[Contributor] elects to include this software in this distribution
 * under the [CDDL or GPL Version 2] license." If you do not indicate a
 * single choice of license, a recipient has the option to distribute
 * your version of this file under either the CDDL, the GPL Version 2 or
 * to extend the choice of license to its licensees as provided above.
 * However, if you add GPL Version 2 code and therefore, elected the GPL
 * Version 2 license, then the option applies only if the new code is
 * made subject to such option by the copyright holder.
 *
 * Contributor(s): Thomas Ball
 *
 * Version: $Revision$
 */

package org.netbeans.modules.classfile;

import java.io.DataInputStream;
import java.io.IOException;

/**
 * An entry in the local variable type table of a method's code attribute.
 * This table is similar to the local variable table, but differs in that
 * it only contains the type information for those variables that are generic
 * reference types.  Local variables that are generic reference types have
 * entries in both tables, while other local variable types are only defined
 * in the local variable table.
 *
 * @author  Thomas Ball
 */
public final class LocalVariableTypeTableEntry {
    
    int startPC;
    int length;
    String name;
    String signature;
    int index;

    static LocalVariableTypeTableEntry[] loadLocalVariableTypeTable(DataInputStream in, ConstantPool pool) 
      throws IOException {
        int n = in.readUnsignedShort();
        LocalVariableTypeTableEntry[] entries = new LocalVariableTypeTableEntry[n];
        for (int i = 0; i < n; i++)
            entries[i] = new LocalVariableTypeTableEntry(in, pool);
        return entries;
    }

    /** Creates new LocalVariableTypeTableEntry */
    LocalVariableTypeTableEntry(DataInputStream in, ConstantPool pool) 
      throws IOException {
        loadLocalVariableEntry(in, pool);
    }

    private void loadLocalVariableEntry(DataInputStream in, ConstantPool pool) 
      throws IOException {
        startPC = in.readUnsignedShort();
        length = in.readUnsignedShort();
        Object o = pool.get(in.readUnsignedShort());
        if (!(o instanceof CPUTF8Info))
            throw new InvalidClassFormatException();
        CPUTF8Info entry = (CPUTF8Info)o;
        name = entry.getName();
        o = pool.get(in.readUnsignedShort());
        if (!(o instanceof CPUTF8Info))
            throw new InvalidClassFormatException();
        entry = (CPUTF8Info)o;
        signature = entry.getName();
        index = in.readUnsignedShort();
    }

    /**
     * Returns the first byte code offset where this variable is valid.
     */ 
    public final int getStartPC() {
        return startPC;
    }

    /**
     * Returns the length of the range of code bytes where this variable
     *         is valid.  
     */
    public final int getLength() {
        return length;
    }

    /**
     * Returns the name of this variable.
     */
    public final String getName() {
        return name;
    }

    /**
     * Returns the generic field type signature of this variable.
     */
    public final String getSignature() {
        return signature;
    }

    /**
     * Returns the variable's index into the local variable array
     *         for the current stack frame.
     */
    public final int getIndex() {
        return index;
    }
}
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